Ammonia permeation of fluorinated sulfonic acid polymer/ceramic composite membranes

NH3 is potentially an eco-friendly source of energy that normally is produced from H-2 and N-2 via the Haber-Bosch process under harsh conditions (400-500 degrees C and 10-30 MPa) with iron-based catalysts. The recent development of low-temperature active catalysts, however, could allow this reaction to proceed below 250 degrees C. Therefore, the development of a membrane system that could combine these low-temperature active catalysts with membranes selective for NH3 would be beneficial. In this study, the fluorinated sulfonic acid polymers Nafion and Aquivion were used to fabricate novel polymer/ceramic composite membranes. Following characterization by DLS, TG, and FT-IR measurements, Nafion and Aquivion solutions were coated onto ceramic porous supports and dried at 150 degrees C for use in fabricating fluorinated sulfonic acid polymer/ceramic composite membranes, and the permeances for NH3, H-2, and N-2 were evaluated. In comparisons with conventional polymer membranes, the fluorinated sulfonic acid polymer/ceramic composite membranes were thermally stable even at 200 degrees C. The Nafion and Aquivion-H+/ceramic membranes showed single-component NH3 permeance that reached >9.30 x 10(-7) mol m(-2)s(-1)Pa(-1) and >1.55 x 10(-6) mol m(-2)s(-1)Pa(-1) at 50-200 degrees C, respectively. Moreover, NH3 permeance of >2.31 x 10(-6) mol m(-2) s(-1) Pa-1 was obtained from Aquivion-H+ with NH3 selectivity >90 for NH3/H-2 and >800 for NH3/N-2 at 50 degrees C in a mixed system.

Automated summary

This study developed a novel polymer/ceramic composite membrane that exhibits stable ammonia permeance at low temperatures, which is beneficial for the application of ammonia as a renewable energy source.